A technology of converting the kinetic energy of wheels into electrical energy (regeneration) in a motor vehicle or the like by actuating a generator utilizing the kinetic energy of wheels while the vehicle is decelerating is known.
An increase in the recovered kinetic energy (i.e. the electric energy generated by the generator) leads to an increase in the braking force (regenerative braking force) acting on the vehicle. For this reason, the deceleration of the vehicle can become higher than expected by the driver. In particular, if the regenerative braking force becomes large when the vehicle is running on a low friction road surface, slippage of the wheels can occur.
To eliminate the above-described problem, a technology in which the regenerative braking force is decreased by decreasing the recovered kinetic energy (electric energy generated by the generator) at the time when slippage of the wheels is anticipated to occur has been developed (see, for example, Patent Document 1).